Various autotransfusion containers which operate under a vacuum to collect blood from a patient during surgery also may be used to reinfuse the collected blood into the patient. Prior art containers traditionally were formed from non-collapsible glass blood collection bottles. The art then evolved to pliable plastic collection bags which, when compressed, would increase the reinfusion flow of the collected liquids.
To prevent the vacuum from collapsing the container, the pliable prior art containers are distended mechanically during the collection procedure. The following patents are representative of such prior art devices. U.S. Pat. No. 4,443,220 discloses the expanding of a cylindrical blood collection bag by engaging a plurality of sleeve-like loops annularly spaced about the collection bag with the elongated tines of a stent. U.S. Pat. No. 4,838,872 discloses a collapsible blood collection bag which is distended by compressing stiffener members connected to the bag. U.S. Pat. No. 4,943,288 discloses a reinfusion bag which is maintained in an open configuration by separating frame members attached to the bag with a pair of crossed-locking arms which extend across the top and bottom of the reinfusion bag.
The prior art also discloses non-mechanical means for holding the collection bag in an open or expanded configuration during the vacuum influenced fluid collection procedure. U.S. Pat. No. 3,866,608 discloses the application of a second vacuum between the surface of the collection bag and a rigid outer container to prevent container collapse. U.S. Pat. No. 4,781,707 discloses a hermetically sealed chamber between a flexible collection bag and an outer container which prevents the collection bag from collapsing during the blood collection process.
These prior art devices have certain disadvantages. The portions of the plastic collection bags which are not directly attached to the mechanical support structure tend to partially collapse when the vacuum is applied to the container interior. Consequently, the volume scale provided on these plastic containers gives an inaccurate measure of the volume of fluids being collected. That discrepancy may prove harmful when a course of treatment is based on the amount of blood loss. The vacuum expanded containers provide a more reliable container volume but are more difficult to operate. Release of the outer vacuum, which is required to allow the inner container to collapse during reinfusion of the collected blood, has proven problematic.